This invention relates to tactile stimulators and more particularly to a tactile stimulator for use in a photoelectronic reading device for the blind.
Several years ago the present inventor devised an optical to tactile converter device to allow blind people to read. This device converts printed or other optical text or material directly into a corresponding tactile image by means of an input silicon photo-camera which senses the imput image and produces a corresponding pattern of output signals which operate an electromechanical tactile stimulator. In the original device the tactile stimulator was comprised of ceramic bimorphs which vibrate pins in a two dimensional array to produce the output tactile image.
The tactile array produced using bimorphs is extremely expensive to assemble, is quite susceptible to damage in use, contributes significantly to the size, weight and cost of the reading instrument, and is noisy.
Various alternatives have been studied for the original bimorph array including the use of piezoelectric polymers, such as polyvinylidene fluoride (PVF.sub.2). The first approach taken was to fabricate individual PVF.sub.2 cylindrical tactile stimulators. This was found to be virtually unfeasible because of manufacturing difficulties in making electrode connections and in the signal strengths required to extend the cylinders.